What's in the workshop this week, Pelikanblau edition

[MikkiJayne]

Every D2 I have has these same cracks in the sound deadening:

Vera's



Dolphin Grey



Stock 2.8Q



Parts FE



Avus FE



Its caused by this little buffer on the control arm hitting the body as a last-resort to stop the suspension tearing itself apart when it runs out of travel



The welds on the turrets are all different. Whether this is just limitations of the machines back then, or they were done by hand I don't know.

This is the Avus FE - notice how the weld extends past the end of one piece:



This is the parts FE - notice here how the weld missed the end of the lower panel and leaves a sharp corner.



The weld on Vera's stop 10mm sooner than these two and left the same sharp corner.

This is the smoking gun - a sharp corner like this is an ideal place for a crack to start. Bottom out hard and suddenly the mass of the car is stopped as the suspension runs out of travel and all that inertia then puts immense forces on this point and starts a tiny crack which then slowly creeps through the weld with normal driving.

You can see it by removing the cover next to the header tank on the passenger side and the one behind the airbox on the driver's side.